package com.kylin.unsafe;


import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;

////java.util.ConcurrentModificationException 并发修改异常
public class MapTest {

    public static void main(String[] args) {

        /**
         *
         */
        //Map<String, String> map = new HashMap<>();
        //Map<String, String> map = Collections.synchronizedMap(new HashMap<>());
        Map<String, String> map = new ConcurrentHashMap();
        for (int i = 0; i < 30; i++) {
            new Thread(() -> {
                map.put(Thread.currentThread().getName(), UUID.randomUUID().toString().substring(0, 5));
                System.out.println(map);
            }, String.valueOf(i)).start();
        }
    }
}
